Locking plug for extension cords



Dec 4,1928. 7 1,694,056

c. CALKINS LOOKING PLUG FOR EXTENSION CORDS Filed June 16, 1927/nven/'or Patented Dec. 4, 1928.

PATENT OFFICE.

cnorr. OALKINS, or ALBANY, onncon.

LOOKING- ma non nxrnnsron corms.

Application flied Jane 16, 1927. Serial No. 189,834.-

' My invention relates to extension cords,

I electric connections, and similar and like devices wherein it isnecessary to lock the connection when made, and to prevent theaccidental breaking fof the connection when made. i p

A further object of my inventionconsists in providing simple andefiicient means'for. the locking of electric connections and moreparticularly those wherein an extension cord is secured to an electriclight socket of the push and pull type and wherein the same may then belocked to prevent the same becoming disengaged.

A still further object of my invention consists in providing a lockingplug for extension cords, as ordinarily used by mechanics and others andwherein the mechanic using the same may be'located in a position whereinit is very diilicult of access and difiicult to return from the workinvolved to reconnect the connection if broken and wherein the movementof the cord has a tendency to cause a disengagement of the extensioncord secured to the socket.

My invention consists primarily of the Pocket. type, as ordinarily usedhaving disorth in the appended claims, and a preferred 7 form ofembodiment ofwhich is hereinafter shown with reference to the drawingswhich accompany and form a part of this specification. a

In the drawings:

Fig. 1 is a side elevation of one of my new and im roved locking plu forextension cords, s own in posit on within the electric circuit.

Fi 2 is a longitudinal section of the assemb ed device.

Fig. 3 is asectional end view, taken on line AB of Fig. 2, lookingin thedirection indi-' cated, the same being made toshow the extension plug inlocked position.

' parts throughout the several views.

Fig. 4 is aside elevation, partially-in section, of the assembleddevice, the same being taken on line B0" of Fig. 3.

Fig. 5 is a frlggamentary, end, sectional view, takenon line of Fig. 2,but the same being made illustrating the assembled device in unlockedposition.

Fig. 6 is a side elevation of the assembled male end of the extensioncord.

Like reference characters refer to like 1 is the threaded end of theextension cord, adapted to threaded engagement with the lamp socket ofthe electric connection and 2 is an extension cord secured to the maleend 8 of the extension cord. 4 is the body portion of the threaded endof the plug having disposed therein electric connections 5 into whichthe extension ends 6 of the male end 3 of the extension cord is made toengage. The male end 6 of the extension cord is mserted within theengagement connection 5 and com pletes the circuit when disposedtherein. An annular disk 7 is disposed against the outer end 4 ofthebody portion and'is rotatable about the central axis 8. The centralaxis.

8 not only serves as the center of rotation of the annular element 7,but the same passes through the collar 9, which I have here shown to be.substantially equal in outside diameter to the body portion 4, thoughthe same may be made of a smaller diameter if found desirable and theouter end of the central axis 8 has disposed thereon a fastening element10 disposed within the seat 11 and maintains a working relationshipbetween the body ortion 4 and the collar 9. Two arcuate s ots 12, aredisposed within the. disk 7 and each rotation of the 4 the recesses 16are inthis position relative to the connections 5, the extension ends 6may readily be inserted in or withdrawn from the connections 5. Topermit the rotating of the disk 7 after the ends 6 have been insertedwithin the connections 5, each end is provided with a recess 14 toafford a clearance between the edge of the disk 7, and which admits ofits rotation to the right whereby the edge portions of the disk enterthe aforesaid recesses and thereby prohibit the withdrawal follow.

What Ielaim is:

1. In a device of the class described, the combination with a plucomposed of two separable members, one 0 said members having rojectingextension ends and the other mem er having connections within which theaforesaid extension ends are removably 1nserted, of a diskfc'arried bythe last men tioned member, said disk adapted for rotation, and meansfor limiting the extent of said rotation; each provided withva groovespaced from the end thereof, said disk when rotated in one directionhaving portions entering the aforesaid 1 grooves, and when rotated inthe opposite direction having portions avoiding said groovessubstantially-as described.

2. In a device of the class described, the combination with a plugcomposed of two separable members, one of said members having projectingextension ends, and the other member having connections within which theaforesaid extension ends are removaglv of said extension ends being,

inserted, of a disk carried by thc last mentioned member adapted forrotary movement relative thereto, said disk being provided with aplurality of arcuate slots, a stationary pinprojecting through each slotto alford means to hmitthe extent of rotation of said disk; eachof saidextension ehds being provided with a groove spaced from the end 3. In aevicc of-the class described, the

combination with a plug composed of two separable members, one ofsaidfinendiers hav ing projecting extension ends,- and the other memberhaving connections within which the aforesaid extension'ends arercmovabiy inserted, of.a disk carried by the lastmentioned memberadapted for rotary movement relative thereto, and means for limiting theextent of such rotation, each of said exten sion ends being providedwith a groove spaced from the end thereof, said disk when rotated inone-direction having portions entering the aforesaid grooves, and thesaid disk being provided with two diametrically opposite recesses in theedge thereof, which when said disk is rotated in the opposite direction,oppose the recesses in the extension endsthereby admitting of thewithdrawal of the extension ends from the connections substantially asdescribed.

CECIL CALKINS.

